As a common method for user authentication, a password authentication method is being used. The password authentication method stores a password initially inputted from a user, compares a user inputted password to the previously stored password whenever needed, and when they are identical, and determines that the password authentication is successful. Also, technology for authenticating a user using a touch pattern set by the user, evolved from a traditional password authentication method, was disclosed. Korean Patent Application Publication No. 10-2009-0013432 discloses a mobile terminal for authenticating a user using a pattern and its locking and unlocking method.
However, a password has various probabilities of leak. For example, a password may be stolen from a third party having peeped a password input process of a user. Also, a password key-entered in a user terminal may be hacked by a hacking program.
Accordingly, there is a need for technology for protecting user data such as a password from hacking more safely.